textproduct: Quad Cities

KEY MESSAGES

- Periods of showers and storms later tonight through Tuesday. The best chances of showers and storms through Sunday will be during the evening and overnight hours.

- There is also a risk of severe thunderstorms across the entire area Friday night through Monday night. Isolated severe storms are possible Friday night and Saturday night with more widespread severe thunderstorms possible Sunday through Tuesday. The best threat for severe storms is on Monday.

- Temperatures will be warmer Friday through Tuesday of next week with high temperatures in the 80s and increase humidity.

SHORT TERM /THROUGH FRIDAY/

Issued at 158 PM CDT Thu May 14 2026

Zonal flow aloft is forecast across the region with two shortwaves moving across the area. The first of these short waves is forecast to move across the Highway 20 corridor this evening and bring a 20 to 30% chance of showers and isolated thunderstorms. Model soundings show elevated storms with the potential for small hail.

A second shortwave is forecast to move through the flow overnight across northern Missouri after 06 UTC Friday with a developing 30 to 40 knots low level jet with the 850 mb wind convergence across far southern Iowa overnight. There is a risk for isolated severe storms overnight with hail up to the size of quarters possible mainly in far northeast Missouri. The best chance for showers and storms is along and south of a Fairfield to Galesburg line. Rainfall amounts will be very light with up to two tenths of an inch. Low temperatures tonight are in the mid 50s.

Quiet weather is forecast during the day on Friday with noticeably warmer temperatures ranging from the lower 80s east of the Mississippi River and mid 80s west of the river. Breezy southerly winds are forecast to develop Friday with gusts of 20 to 25 mph.

LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/

Issued at 158 PM CDT Thu May 14 2026

During the long term period, the flow aloft is forecast to be zonal with a transition to a amplified southwesterly flow aloft. This will lead to periods of showers and thunderstorms across part of the area Friday night through at least Monday night/Tuesday before there is a return to broad zonal flow aloft. These will also leads to the potential for severe thunderstorms Friday night through Tuesday.

Friday night, a similar convective evolution is expected to late tonight, this time though, a more northerly track is possible, as shown in at least 50% of guidance. With a warmer atmosphere in place, inherently more unstable in the boundary layer than tonight, this offers a low, but more mixed potential for severe weather of both large hail and damaging winds, though once again, we may be towards the later half of the storm evolution Friday night, with threats decreasing with time. There is a marginal or level 1 out of 5 risk of severe weather on Saturday with slight risk (level 2 out of 5)of severe thunderstorms.

The global ensembles favor zonal flow aloft becoming southwest flow this weekend into early next week as an upper level trough deepens across the Intermountain West. With Gulf moisture return, this will set the stage for multiple rounds of thunderstorms. Surface dewpoints are forecast to increase into the mid 50s F by Saturday and at least into the 60s by Sunday and potentially the lower 70s by Monday. When combined with increasing temperatures into the 80s, buoyancy will also be on the increase across the region, especially Sunday into Monday.

SPC has portions of the region outlooked in Marginal to Slight Risks from Saturday through Tuesday. Within this period, Monday has the more significant threat for all severe weather hazards (large hail, damaging wind and tornadoes), followed by Sunday afternoon into Sunday night.

From a setup standpoint, the wavering front remains over the area through Saturday, and then begins to lift north on Sunday as a warm front with a large warm, buoyant sector establishing itself across much of the central US on Monday. Buoyancy will build to the south of this stalled turned stationary turned warm front. The best chance for thunderstorms Saturday looks to be south of I-80, south of the stalled front. There is some question as to the strength of forcing and shear for thunderstorm coverage and organization, and the SPC Marginal Risk for the southern portions of the area describes the threat well for Friday night, with a small area of a Day 3 Slight Risk in south central Iowa on Saturday into Saturday night.

Buoyancy continues to build into Sunday. As stronger impulses embedded in southwest flow aloft arrive and the low level jet strengthens Sunday evening and night, the coverage and organization of storms will be greater than compared to Saturday. Monday poses the more significant severe thunderstorm threat from a coverage and organization standpoint with a higher ceiling for all hazard magnitudes for large hail, damaging wind and tornadoes. As low pressure propagates into the Upper Midwest on Monday, with strong mid and low level jets, forcing and shear will be maximized coincident with moderate to strong buoyancy. Specific details and timing will be worked out over the coming days, however, machine learning severe probabilities all point to Monday being the most significant day for severe thunderstorms.

Severe storms are possible on Tuesday but that depends largely on the timing and location of a cool front from Monday night that will move across the area. The GFS is much faster with the timing of this front than other models including the ensembles with the slower solutions showing showers and thunderstorms lingering into Tuesday and thus a possible severe threat.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 615 PM CDT Thu May 14 2026

A dry air mass over the region early this evening results in the forecast challenge of how widespread showers and storms will be later tonight. For much of the area north of U.S. Highway 34, we expect the dryness to keep coverage to more scattered and confined to the general 05-10Z period. Southward in the region, including BRL, coverage is likely to be greater with some embedded thunder. In the wake of any rain tonight, some broken 3,500-5,000 ft clouds may develop and linger through Friday morning, with a presently <20% chance for MVFR cigs.

Southerly winds should stay at 10-14 kt tonight with sporadic gusts, even some above 20 kt at CID and DBQ. Similar winds look to continue through the day Friday as well.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.